Method of obtaining luster in cotton fabric by mercerizing and calendering the fabric



C. FETSCHER July METHOD OF OBTAINING LUSTER IN COTTON FABRIC BY MERCERIZING AND CALENDERING THE FABRIC Filed Nov. 25, 1948 2 Sheets-Sheet 1 INVENTOR CHARLES FETSCHER 44 f9 July 21, 1953 METHOD 0 MERC BY Filed Nov. 23, 1948 F OB ERIZ c. FETSCHE 2,646,341

R TAINING LUSTER IN COTTON FABRIC ING AND CALENDERING THE FAB beets-Sheet 2 VENTO CHAR FETS R BY 0M. AMIM.

Patented July 21, 1953 METHOD OF OBTAINING LUSTER IN COT- TON FABRIC BY MERCER-IZING AND CAL- ENDERING THE FABRIC Charles Fetscher, Troy, N. Y., assignor to Cluett, Peabody & 00., 1110., Try,'N. Y., a corporation of New York Application November 23, 1948, Serial No. 61,546

4 Claims. (01. s 125) This invention relates to the treatment of cotton-containing fabrics to improve the appearance and hand thereof, and particularly to impart to such fabrics a high, silk-like luster and hand which surpasses the appearance given by the mercerizing of cotton fabrics. Various attempts have "been made to treat cotton-containing fabrics to improve the luster thereof, but difiiculty has been experienced in having the improved luster ,and hand permanent under repeated launderings. 1

I have discovered that cotton-containing fabrics may be given a durable, silky appearance or luster, which will be permanent under repeated launderings in boiling water, and that the treated fabric will not suffer any substantial loss in tensile strength or abrasion resistance. The improved treatment includes a method which imparts the desired characteristics to the fabric, and also improved apparatus for carrying out such method.

In the accompanying drawings:

Fig. 1 is a plan of a simple apparatus that may be employed to impart a permanent luster or silky appearance and hand to cotton-containing fabrics in accordance with this discovery, the upper calender and padder rolls being broken away in the lower half of the View;

Fig. 2 is a longitudinal, sectional elevation through the same parts, but with the parts shown somewhat diagrammatically;

Fig. 3 is a side elevation of a part of the chain or carrier which holds the fabric against shrinkage in a weftwise direction during part of the treatment;

Fig. 4 is a transverse sectional elevation of the parts shown in Fig. 3, the section being taken approximately along the line l-t of Fig. 3; d

Fig. 5 is a sectional elevation of a part of the machine, the section being taken approximately along the line 5-5 of' Fig. 2; and

Fig. 6 is another sectional elevation of a part of the same, the section being taken approximately along the line 66 of Fig. 2.

In previous attempts to impart a silky luster and hand to cotton fabrics, those methods which had any merit involved the use of pressure to flatten out'the irregularities in the fiber surfaces and leave the fibers broad, smooth andrefiectin'g.

and-appearance or high luster, may be given to 2 the cotton fabrics by first thoroughly softening or highly plasticizing the fibers thereof and then subjecting them to high pressureto flatten them,

out, so that the fibers will retain their flattened shape when subsequently laundered.

I have further discovered that the plasticizing or softening of the cotton fibers, so that they will retain their flattened shape, is most effectively obtained by wetting the cotton fabric with a caustic solution of mercerizing strength, such'as Th temperature of the treating solution does not appear to be critical, and temperature changes from 0 C. to C. do not appear to produce any decided or definite effect on the fibers. Room temperatures are entirely satisfactory, and give very good results. When the fabric is wet with caustic solution of mercerizing strength the fibers swell and become plastic; The

excess caustic solution is then removed, such as I by passing the wet fabric between padder rolls, or with blotting paper, or centrifugally, 'or by any other manner.

After the fabric has been Wet with such caustic solution until the fibers have swollen and become very plastic, the fabric is given a light rinse; usually withwater, to'remove some of the caustic, which appears to cause a further swelling of the fibers by osmotic pressure. The temperature of the'rinse water is not critical, and this prelimi-- nary rinse can be omitted if desired, but because r of the fact that it appears to give further swelling to the fibers, it is desirable. The fabric, with swollen and plastic fibers, is then subjected to a heavy face to face pressure which flattens the fibers and'presents a relatively broad, smooth surface on the fabric fibers. The higher the pressure applied, generally the better the luster imparted to the fabric, except that if a substantially heavy pressure has been applied, the improvement in luster given to the fabric by further increasing the pressure does not always give proportionately. better results.

Excellent results. have been obtained with pressures as low as about fifty (50) pounds per square inch on the plasticized fibers, and reasonably satisfactory results for some purposes have been obtained with pressures as low as about forty (40) pounds per square inch. Excellent results have also been obtained with pressures on the fabric as high as fifteen thousand (15,000) pounds per square inch.

The temperature at the time of pressing does not appear to be sharply critical, but the results appear to be best when the temperature at the time of pressing is from about 150 F. to 350 F. The fabric preferably is passed through a partial rinse, pressed, then partially rinsed and again pressed, and then further partially rinsed and then again pressed. This repeated pressing and partial rinsing occurs for several steps. An advantage of the partial rinsing before and between successive pressings of the fabric appears to be that the rinsings progressively remove the caustic, so that the caustic will not keep the fibers plastic after the pressing, or destroy the silky appearance. Thus the flattening of the fibers of the fabric is carried on while the caustic is being removed, and in this manner the plasticity of the cellulose is reduced in a step by step manner.

It is recognized that when a cotton fabric is subjected to a caustic solution of mercerizing strength, the fabric tends to shrink rather heavily unless shrinkage is prevented. The heavy shrinkage results in a loss of yardage of the fabric, which is a serious economic loss. The cotton fabric which is treated with a caustic solution of mercerizing strength does not receive a luster from the caustic unless the fabric is kept under tension during treatment.

I find it desirable, therefore, to hold the fabric from shrinkage while the fibers are plastic, and accordingly the fabric, while the fibers are still plastic, is held to its normal width following the caustic treatment and during the repeated calenderings and rinsings. By such treatments, one obtains the silky hand and appearance or high luster on the fabric, without any large loss of yardage due to shrinkage.

In the drawings I have illustrated, somewhat diagrammatically, a simple apparatus that may be employed to carry out this improved method, and it will be understood that various other types of apparatus may also be employed for the same purpose.

In the illustrated embodiment of the apparatus, a web I of cotton-containing fabric is passed, by endwise progression, through the housing or frame 2 in any suitable manner. Within the housing is a tank 3 for applying caustic solution, and the web I, after passing over the idle roller 4, passes downwardly into the tank 3, around roller 5 in the tank, then upwardly well above the tank 3, and then over the idle roller 6. The fabric is then engaged by a clip expander mechanism of the type illustrated in U. S. Patent No. 2,082,981, of June 8, 1937. Reference to that patent may be had for a full disclosure of this type of expander device, which includes opposing diverging stretches of a traveling, edge-holding endless carrier or device that engages the selvedge edges of the web and pulls it to the desired width. In View of the full disclosure of this type of device in said prior patent, that type of holding device is shown only diagrammatically in the drawing.

As shown, the clip expander includes spaced, endless carriers 1, one at each side, which pass around pulleys 8 and 9 at each side. Each carrier 1 is provided with clips which automatically engage and grip the edge of the fabric, and it will be noted that the adjacent stretches of the carrier 1 diverge in the direction of their travel, so that as the edges of the fabric are engaged by the clips on the carrier 1, the movement of the carriers will not only carry or move the web further through the frame, but will also pull it to the desired width, depending upon the degree of divergence of the stretches of the carriers 1 which engage the fabric web.

After the fabric has been pulled to its full width by this clip-expander, it is released from the clips as the carriers pass around pulleys 9, and then is at once passed through a padder or wringer device I0 formed of a pair of superposed rolls, mounted to rotate, in the upper part of the frame 2. The web, after passing through the padder, immediately is engaged by another endless carrier II somewhat resembling a pin tenter, one of which is shown in U. S. Patent No. 1,734,897, of November 15, 1929. This device engages the selvedge edges of the fabric and keeps the edges separated throughout the remainder of their travel, until the fabric treatment has been completed and the fabric is ready to be discharged from the housing, or frame, 2.

A simple form of such carrier H is illustrated in the drawings, somewhat diagrammatically, in Fig. 2, but is omitted, for clarity, from Fig. 1. It includes two endless chains, one at each side of the frame 2 on the interior thereof. Each chain passes around sprocket wheel l2 and I3 and then around sprocket wheels formed as a part of the calendering devices M (Fig. 2).

A plurality of such calendering devices are arranged in succession along the frame 2, so that the web I may pass through these devices in succession. Calendering devices of this type are well known in the art, and hence, have been shown only diagrammatically. Each of such calendering devices employs a pair of calendering rolls l6 and I! which are arranged in a relatively superposed relation, with one of them, such as upper one, urged against the other roll by heavy pressure, usually through springs or a compressible medium such as compressed fluid. One (or both) of these rolls is usually heated so that the fabric passing between the rolls will not only be flattened under heavy pressure, but will also be heated, which tends to drive off some of the moisture carried by the fabric. These rolls are usually hollow with chambers A and axial passages B in their trunnions. They may be heated internally by steam or by electric heaters incorporated therein, or they may be externally heated if desired.

The lower roll of each of these calendering devices [4, see Fig. 6, carries a sprocket wheel [8 which is secured over the hub I9 of that roll by screws 20. The ends of the upper and lower rolls l8 and I! have aligned annular grooves 2| and 22, which provide between them a clearance space through which the selvedge edges of the fabric web may pass. The carrier II is made up of two endless chains, each somewhat resembling the well known bicycle chain, and having pivotally connected units. Each unit is formed of a pair of links 23 spaced apart by sleeves 24, Fig. 4, and links 25 fit against the opposite sides of the links 23 and are hinged to the units to connect them. Pivot pins or rivets 26 pass between the overlapping ends of the pairs of links 23 and 25 and through the sleeves 24 to serve as a pivot between the chain links.

Each of the links 23Iand 25 at one side of. the carrier H is provided with anupstanding ear or lug 21 which extends above the links and is then bent laterally to provide an arm 28. These arms 28 on successive links 23 and'25 are all in the same plane when the successive links are in a straight line, as shown in Figs. 3 and 4, and each of these arms 28 carries a row of upstanding pins 29 aligned with the pins of adjacent arms of the same carrier and over which may be impaled the adjacent selvedge edgesof the web. Between the calendering devices, the frame. 2 carries, on its'inside face, shelves 30-upon which the upper stretch of each carrier. II is guided. The free edge-"of each shelf 30 isprovided with an upstanding flange 3|, which-acts as a rail or guide to prevent the chain from being pulled sidewise. Therefore, as the adjacent selvedge edge of the fabric is engaged over the pins 29 on a carrier, any subsequent shrinkage in width of the fabric will be resisted, since the carriers l I will be held against movement toward each other while traveling along the upper stretch. 7

Also carried by each side wall of each shelf 30 is a flange 32,"see Fig. 4, that extends above the adjacent side links 23 and 25, and those links ride along the under face of these flanges 32' and are held thereby from any tilting to the leftdue to any Weftwise pull of the fabric on the arms .28.

The rolls of each padder H] are suitably mounted to rotate in the frame 2, and each roll may be formed of a rigid or metal core 33 for the lower roll and 34 for the upper roll; Eachcof these rolls is provided with a sleeve or cover 35 of resilient rubber, see Fig. 5. The lower roll 33 of each padder is provided at each end with an an-' nular rabbet or groove 36, and theupper roll 3.4 is similarly provided with a Vertically aligned annular groove 37. These two grooves together form a passage or channel 38 through which the arms 28 with their prongs 2'! may pass as the carriers ll carry the selvedge edges of the fabric forwardly through the frame or housing 2.

The lower roll 33 of each padder is also provided with a deep groove 39 at each end through which carrier H may pass, as shown in Fig. 5, above the axis of rotationof the lower roll. Each of the padder rolls may, if desired, have a detach able stub or end shaft 40 which is received. in an end of an axial passage 41 in the roll, and held detachably imposition therein by a set screw 42 in the end hub of the roll which engages an annular groove 43 in the shaft 40. Spacer plates or washers 44 may be provided between the ends of the padder rolls and frame 2 to take up end wear or thrust.

Referring now to Figs. 1 and 2 each calender roll carries a gear 45, and the two gears on each carries a bevel gear 49, which meshes with andisdriven from another bevel gear 50. All of the gears are: fixed on a common shaft 5|, which is rotatably supported by the frame 2, in suitable This shaft 5| extends in a direction lengthwise of the-frame and carries thereon-a bearings.

gear 52, which is driven from some suitable source of power that serves to drive all of thecale'nder rolls at the same speed. The shaft 5| also carries a 45 helical gear 53 which meshes with and drives another similar gear 54, see Fig. 1, which is fixed on a shaft 55 that extends crosswise of frame 2, and is rotatably supported thereby.

, The shaft 55, adjacent to each side, carriesa ranged over the portion of the web passing between the idler roller 6 and the padder Ill, was to spray rinse liquid upon the web'that has passed through the caustic tank 3 and over the idle roller 6. In the particular example illustrated, a

, plurality of such heads 59 are arranged in a row transversely across the web on a pipe 60 that supplies the rinse liquid from a suitable source under pressure. The rinse liquid is usually water.

Similarly, a plurality of additional supply heads 6| are disposed in a row across the web, between the first and second calender devices, and are mounted on a common supply pipe 62 which serves to support the heads and supply rinse liquid such as water thereto. Spray heads 6! are similarly supported on a branch of pipe 62, in a row across and above the Web between the second and third calender devices. Thus, a common supply pipe. 62 supportsboth sets of heads 6| and supplies rinse liquid such as water, thereto.

' through the web and such caustic as'is washed off.

'to the last calender of the series.

A drain pipe 6'! controlled by a valve 68 leads from the bottom of this pan 66. The caustic recovered in this manner by pipe 61 may be reused by adding additional caustic thereto to bring the solution up to mercerizing strength and then adding it as replacement liquid for the causticof tank 3 that is used up in wetting the web passing through tank 3.

A padder 69, formed'of superposed rolls and similar to padder III, is disposed just in front of the middle calender and as closely as possiblethereto. The web passes between the rolls of padder 69 just before it enters the middle calender. Another padder TD, similar to padder 69, is similarly placed immediately in front of but close In the operation of this apparatus, the web I of cotton-containing fabric is'passed progressively over the idle rollg4, downwardly into tank 3 containing caustic solution of'mercerizing strength, and below the level of the caustic solution therein, and then upwardly over the idle roll 6. The web then passes beneath spray heads 59 and immediately after leaving roll 6 the edges of the fabric are engaged by the clips on the clip expander, and the expander then serves to pull the caustic-wet fabric web sidewise to its desired or initialwidth,

aeaaear and then the 'web is released and passed through padder 10 which expresses the excess liquid. Immediately thereafter the web passes through the first calender device, between the rolls thereof, which serves to subject the web to very heavy pressure in excess of about forty pounds per square inch and which may extend to pressures as much as three thousand pounds per square inch or more. The calender rolls are preferably heated. internally or externally to about 150 F. or more at the peripheral surface thereof. The web then passes successively-beneath spray heads 61, through padder 69, through the second .calender device, beneath the spray head 6!, through padder 70, and then through the last calender device.

All calender devices are preferably heated to about the same temperature, and may have the same or different pressing pressures.

As the web is passed through the first'ca'lender device its selv-edge edges are impaled'over the needles or prongs 29 on the upper stretch of the carrier II and carried along until leaving the last calender. The carrier H serves to hold the web in its laterally stretched position, so that it cannot shrink weftwise until after it has passed the last calender device .and is released. By that time of release the caustic has been largely, or entirely washed from the web so that the fabric web .has lost its tendency to shrink. A rinsed liquid preferably is sprayed on the web while it is in the clip expander, and again between the calender devices to give a partial rinse'to the web at each of thosestations. The web is held against warpwise shrinkage while traveling through the machine, because the rate of feed of the web at all stations is the same, and consequently the web cannot shrink in length.

A pair of feed rolls (not shown) may deliver the web to the idle roll 4 at the same rate that it is removed from the last calender device, which also prevents any lengthwise shrinkage of the web before it is engaged by the clip expander. The caustic solution in tank 3 wets the web of cotton-containing fibers, and within ten seconds time the cotton fibers will swell and become quite plastic. The web is partially rinsed, by a rinsing liquid from spray heads .59 to further swell the cotton fibers, and then the excess liquid is expressed by padder [0, so that there will .be less tendency for the caustic on the web at the first calender device to reswell the calendered fibers and cause them to lose their luster. Similarly, partial rinsings immediately before each calender operation tend to remove some of the caustic and consequently reduce the tendency of the caustic to destroy the luster. Rinsing with water before each calendering serves to reduce the plasticity of the cellulose of the cotton fibers in a step by step manner, and the progressive rinsing-followed by calendering serves to maintain the smooth surface and lustrous appearance of the web.

The rinsing with the water at the different stations causes some further or reswelling by osmotic pressure, and when this is followed by further calendering under substantial pressures, a permanent flattening of the fibers is secured, so that subsequent washings of the web'will not'destroy this flattened condition of the fibers and the silky or lustrous appearance and hand of the web. The web leaving'the last calender may be passed through any suitable type of washer, which removes any remaining trace of caustic from the web, and then the fabric .may be ished .inthe usual manner without loss or reduction of the luster and hand.

While water alone tends to plasticize fibers of cotton, and some luster may be obtained by using water alone as the swelling or plasticizing agent, nevertheless, water is slower in its swelling action and .does not give the same, full degree of plasticity to the fibers as the caustic appears to impart thereto.

It will be understood that various changes in the details, steps, materials and arrangements of parts, which have been herein described and illustrated in order to explain the nature of this discovery, and the practice thereof, may be made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims.

Iclaim:

1. The method of treating a fabric formed largely of cotton fibers to impartthereto an increased lustre that is permanent to multiple laundry washes, which comprises wetting the fabric with an aqueous caustic soda solution of mercerizing strength until the cotton fibers thereof have approximately maximum swelling and plasticity, then immediately, while the cotton fibers are still swelled and plastic, successively rinsing the fabric with water to progressively remove the caustic soda from the fibers, and after the rinsing has begun and shortly before the caustic has been fully removed, permanently flattening the swelled fibers.

2. The method of treating a fabric formed largely of cotton fibers to impart thereto an increased lustre that is permanent to multiple laun dry washes, which comprises wetting the fabric with an' aqueous caustic soda solution of mercerizing strength until the cotton fibers thereof have approximately maximum swelling and plasticity, then immediately, while the cotton fibers are still swelled and plastic, successively rinsing the fabric with water to progressively remove the caustic soda from the fibers, and after the rinsing has begun and, the caustic soda content of the fibers substantially reduced, permanently fiattening the swelled fibers.

3. The method of treating a fabric formed largely of cotton fibers to impart thereto an'increased lustre that is permanent to multiple laundry washes, which comprises wetting the fabric with an aqueous caustic soda solution of mercerized strength until the cotton fibers thereof have approximately maximum swelling and plasticity, then immediately, while the cotton fibers are still swelled and plastic, holding the fabric against shrinkage and successively rinsing the fabric with water to progressively remove the caustic soda from the fibers, and after the rinsing has begun and, the caustic soda content of the fibers substantially reduced, permanently flattening the swelled fibers. V

4. The method of treating a fabric formed largely of cotton fibers to impart thereto an increased lustre that is permanent to multiple laundry washes, which comprises wetting the fabric with an aqueous caustic soda solution of mercerizing strength until the cotton fibers thereof have approximately maximum swelling and plasticity, then immediately, while the cotton fibers are still swelled and plastic, holding the fabric against shrinkage and successively rinsing the fabric with water to progressively remove the caustic soda from the fibers, and after the rinsing has begun and, the caustic soda content of the fibers substantially reduced, permanently flattening the swelled fibers, by a succession of calenderings under heavy pressures separated by water rinsings.

' CHARLES FETSCI-IER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 600,826 Thomas et a1 Mar. 15, 1898 615,045 Prevost Nov. 29, 1898 994,076 Hahn May 30, 1911 1,030,656 Fretts June 25, 1912 1,441,740 Nelson Jan. 9, 1923 1,747,755 7 Crowell Feb, 18, 1930 1,751,089 Knowland et a1. Mar. 18, 1930 OTHER REFERENCES Matthews Textile Fibers, H. R. Mauersberger,

5th edition, John Wiley and Sons, New York, pages 283, 278. 

1. THE METHOD OF TREATING A FABRIC FORMED LARGELY OF COTTON FIBERS TO IMPART THERETO AN INCREASED LUSTRE THAT IS PERMANENT TO MULTIPLE LAUNDRY WASHES, WHICH COMPRISES WETTING THE FABRIC WITH AN AQUEOUS CAUSTIC SODA SOLUTION OF MERCERIZING STRENGTH UNTIL THE COTTON FIBERS THEREOF HAVE APPROXIMATELY MAXIMUM SWELLING AND PLASTICITY, THEN IMMEDIATELY, WHILE THE COTTON FIBERS ARE STILL SWELLED AND PLASTIC, SUCCESSIVELY RINSING THE FABRIC WITH WATER TO PROGRESSIVELY REMOVE THE CAUSTIC SODA FROM THE FIBERS, AND AFTER THE RINSING HAS BEGUN AND SHORTLY BEFORE THE CAUSTIC HAS BEEN FULLY REMOVED, PERMANENTLY FLATTENING THE SWELLED FIBERS. 